The present invention relates generally to vehicle engines and particularly to four-stroke vehicle engines using rotary valves to input a charge to a cylinder of the engine and exhaust the residual from the cylinder of the engine.
The use of rotary valves in the present invention eliminates a number of heavy castings, such as the inlet and exhaust manifolds, and other mechanical parts over such conventional engines as a standard poppet valve four-stroke engine as is conventionally used in motor vehicles today. The present rotary valve constructed disclosed and claimed herein has the capacity to be of lesser weight and capable of lower cost than a conventional four-stroke engine, and equally, if not more, mass producible, along with fewer mechanical problems from the standpoint that fewer mechanical parts are used.
Although several types of rotary valve constructions have been proposed in the past, none have become commercially feasible. One problem is that the majority of the rotary valve constructions proposed in the past needed substantial modification to the engine. Thus, a further object of the present invention is that a tubular rotary valve construction is provided that can be mounted on a conventional four-stroke engine block as a head replacement with little or no modification to the block. The rotary valves are integrated into the engine head to be readily applicable to in-line engine blocks in particular, although the present invention can also be used on "V" or radial engines. The maximum advantages in low weight and low costs, however, occur with in-line engines.
Another problem with prior art rotary valve constructions is that they are not readily machineable and mass producible. Thus, the present invention has a further object of being readily machineable and mass producible in order to be placed in a conventional assembly line for production of automotive vehicles or the like.
It is a further object of the present invention to minimize dead space or unused space within the combustion chamber and provide a rotary valve construction where the charge enters and the exhaust exits the cylinder at the top of the cylinder above the piston. Minimizing dead space uses the charge more efficiently and permits more charge to enter and be combusted in the working chamber of the engine for a given displacement since less residual will remain in the working chamber with the present construction.
In accordance with the object of the present invention to provide a lighter weight engine than a conventional engine, the present invention has still another object of providing a rotary valve construction with minimal external manifolding in place of the heavy castings and camshafts that exist in most conventional four-stroke engines today. Also, this minimal manifolding is to be provided with the capability of permitting the carburetor and/or an exhaust extension to be situated anywhere around the vehicle engine, including above the transmission in a transversely mounted engine or above the engine as is conventionally done on a longitudinally mounted engine.
Also in accordance with the object of providing an engine of lighter weight is the object of the present invention to be capable of providing an even smaller head and a smaller engine than a conventional engine with the same power and displacement. In the present invention, very little spacing is necessary between the cylinder bores, very little spacing is necessary between the valve bores, and the valve bores can be spaced from one another along a plane intersecting the centerline of the cylinder at an acute angle to compact the head even further.
A still further object of the present invention is to minimize any eddy losses and take advantage of vortex or swirl effects in manifolding the charge and the exhaust through the valves. A modified embodiment of the present invention theoretically should reduce any eddy losses by approximately 30% at the inlet and over 60% at the exhaust over the non-modified version of the present invention, while also taking advantage of the vortex or swirl effects.
With prior art rotary valve constructions, and all conventional poppet valve constructions, lubrication is generally a major consideration. The present invention, however, is readily amenable to be lubricated via conventional oil lubrication systems. Also disclosed herein is an improved wiper or wick type lubrication system for the valve of the present invention. A further option is a spring loaded wiper system for lubricating the valve using a lead graphite wiper or other solid dry lubricant.
Another object of the present invention is to provide all of the above objects in a manner also compatible to racing engines for vehicle racing where a large amount of change is desired to be fed to the inlet and exhausted in a much more rapid fashion than in a conventional vehicle engine.
The present invention can be implemented either for a single cylinder engine or a multi-cylinder engine. Bearings having close tolerances may be utilized since the present invention is highly amenable to accurate machining by having the parallel valve bores machined simultaneously side by side. Thus, the present invention has the advantage of a close tolerance bearing, wherein only one position key need be used for even a multi-cylinder engine.
Another further object of the present invention in the multi-cylinder engine embodiment thereof is even distribution of the fuel mixture. In the present invention, baffles may be utilized within the interior manifold of the inlet rotary valve to improve distribution of the fuel mixture and break up laminar flow to more properly mix the fuel and air mixture, or at least keep the fuel and air mixture from separating. The baffles would vary in design according to the engine application, but may include a compartmentalized baffle. Likewise, on the exhaust side, a combination exhaust valve and manifold exists as one of the advantages of the present invention.
The present invention also has the further object of being capable of use with a variety of fuels. This object also includes usage with engines having fuel injection systems distributing fuel directly to each cylinder, wherein the engine valve system of the present invention would provide a desired amount of inlet air and exhaust the residual mixture. Alternatively, the present invention has the object of being used with propane, hydrogen fuels, or any other fuels.
A still further object of the present invention is a greater efficiency than conventional poppet valve engines. The present invention does not require the horsepower usage needed in driving the cam shaft end of a poppet valve engine against the spring tensions of the poppet valves. Even more horsepower is used with higher performance of the engine. Also, the present invention on the exhaust side is believed to eliminate the hot spots on the exhaust poppet valves, which allows the present invention to run more totally advanced. Furthermore, on the inlet side, the inlet is almost instantly heated, unlike the cold initial inlet on a conventional engine or any other engine with external manifolding, to provide very good vaporization sooner than other externally manifolded engines. Low idle characteristics are also evident in the present invention to improve fuel economy in city driving.